OSIR, September 2019, Volume 12, Issue 3, p.84-92 Epidemiological Trends of Malaria in Eastern Shan State, Myanmar 2000-2016 Ba Soe Thet1,2*, Witaya Swaddiwudhipong3, Krongthong Thimasarn4, Aung Thi5, Than Naing Soe6, Zaw Lin7 1 International Field Epidemiology Training Programme, Epidemiology Division, Ministry of Public Health, Thailand2 Vector Borne Disease Control Unit, Eastern Shan State, Myanmar 3 Mae Sot General Hospital, Tak Province, Ministry of Public Health, Thailand 4 Department of Disease Control, Ministry of Public Health, Thailand 5 Department of Public Health, Ministry of Health and Sports, Myanmar 6 Department of Public Health, Ministry of Health and Sports, Myanmar 7 Eastern Shan State Public Health Department, Ministry of Health and Sports, Myanmar *Corresponding author, email address: [email protected] Abstract Malaria is a priority communicable disease in Eastern Shan State (ESS) of Myanmar. This study aimed to describe the malaria situation, epidemiology and treatment services in ESS during 2000-2016. Data from township malaria monthly reports in ESS during 2000-2016 were analyzed by time, place, person, species and treatment services. Malaria morbidity, mortality and case-fatality rate decreased from 25.0 to 3.7 per 1,000 population, 15.0 to 0.2 per 100,000 population and 4.6% to 1.3%, respectively, during 2000-2016. The male to female ratio was 3:2 and those over 15 years old constituted 60% of all cases. The number of cases declined by 88% and 99% among those younger than 5 years of age and pregnant women, respectively. During 2011-2016, the case detection rate increased from 2% to 12%, and 94% of blood examinations used a rapid diagnostic test. Plasmodium vivax (63%) was the most prevalent parasite species, followed by Plasmodium falciparum (33%) while mixed parasites accounted for 4% of all infections. Non-government-controlled areas contributed more than 80% of cases between 2013 and 2016. Remarkable reductions in malaria morbidity and mortality in ESS followed improvements in early detection, appropriate treatment and effective vector control. However, the overwhelming contribution on caseload in non-government-controlled areas remain a challenge for the elimination of malaria in Myanmar. Keywords: malaria, morbidity, mortality, annual blood examination rate, Eastern Shan State, Myanmar Introduction incidence of malaria to less than one case per 1,000 population in all states/regions by 2020 by scaling up In 2015, there were an estimated 212 million cases of malaria control interventions.2 malaria and 429,000 malaria-related deaths globally. Eastern Shan State (ESS) is situated in the most In the South-East Asia Region, about 1.4 billion eastern part of Myanmar and consists of ten people were at risk of malaria, with 237 million at townships, eight sub-townships, 71 wards, 147 village high risk in 2015.1 Malaria in Myanmar contributed tracts and 2,063 villages with a population of approximately two-thirds of both morbidity and approximately 800,000. According to area micro- mortality in the Greater Mekong Subregion during stratification of ESS in 2015, about 53% and 28% of 2013.1 As a result, the National Malaria Control the population lived in malaria risk areas and Programme (NMCP) was developed in coordination with both international and local agencies, including probable risk areas, respectively. Because of the high the World Health Organization to reduce the proportion of the population at risk of infection, 84 OSIR, September 2019, Volume 12, Issue 3, p.84-92 community-based malaria control interventions were reported malaria cases: outpatients (OP): those who developed and have been implemented since 2007 in had uncomplicated malaria, and inpatients (IP): those ESS to increase accessibility of quality diagnosis and who had severe malaria, were hospitalized and had a effective treatment, especially in remote areas.3 For high risk of death.4 example, microscopy has been used for malaria The OP malaria case definition varied from year to diagnosis in health centers where microscopes are year depending on the type of blood test performed. available and malaria rapid diagnostic tests (RDTs) In the past, the NMCP diagnosed patients with have been used in all healthcare settings ranging positive blood films as “confirmed malaria cases” and from health centers to the community level. The basic “clinically suspected cases” based on clinical reporting units are village health volunteers (VHVs) symptoms. In 2006, the NMCP introduced, to some and basic health staffs. All examined cases are health centers, RDT which could detect only P. recorded in carbonless case registers and reported falciparum species. Since 2011, the NMCP has been monthly.4 distributing (through the State VBDC) bivalent RDTs, Eastern Shan State has experienced many malaria which can diagnose P. falciparum and P. vivax epidemics. One major epidemic occurred during 2001 malaria and, therefore, all malaria cases were in which an estimated 10,000 persons were affected regarded as confirmed cases.4 with 1,066 reported deaths in 23 villages.3 In addition, because ESS contains many so called "special Data Analysis regions" (politically unstable areas), non-government We analyzed data between 2000 and 2016 for controlled areas, and extremely hard-to-reach areas, morbidity and mortality rates, OP and IP malaria it is classified as a high risk malaria area.3,5 cases and deaths by time and township. We also Consequently, the extent of malaria and treatment described the distribution of cases by type of service service coverage is largely unknown. The objective of (i.e. health facility, village health volunteer and this study was to describe the malaria epidemiology NGO/INGO), gender age and species from 2011-2016 and coverage of treatment services in ESS during because data prior to this period were not available. 2000-2016 in the presence of malaria intervention We calculated the annual blood examination rate activities. (ABER) and annual parasite incidence (API) and used ArcGis 10.1 software for mapping. Methods Descriptive statistics including frequency, rates and We conducted a descriptive study on malaria in ESS proportions were computed. We calculated malaria during 2000-2016. morbidity rates per 1,000 and malaria mortality rates Data Sources and Data Collection per 100,000. We calculated ABER from the number of patients examined by microscopy or RDT per 100 We reviewed aggregated data on malaria cases and population and API rate per 1,000 population at-risk.6 deaths during 2000 – 2016 from the Vector Borne Disease Control (VBDC) programme at the state level. Results The data included monthly reports, carbonless Malaria Morbidity and Mortality Rates, 2000-2016 registers from townships, State VBDC annual reports Figure 1 shows the trends of malaria morbidity (per and reports from international non-governmental 1,000 population) and mortality rates (per 100,000 organizations (INGOs) and non-governmental population) in Eastern Shan State between 2000 and organizations (NGOs). However, malaria data of time, 2016. The morbidity and mortality rates gradually place, person and type of species were not available declined between 2000 and 2009 and then remained before 2011. Data on case detection and management fairly steady over the next 7 years. In 2000, the by type of service are available only after 2012. malaria morbidity rate was 25 per 1,000 and the Operational Definition mortality rate was 15 per 100,000 population. In 2016, the malaria morbidity rate was 3.7 per 1,000 and the A confirmed malaria case was defined as a patient mortality rate was 0.2 per 100,000. The highest whose blood film was positive by microscopy or rapid morbidity rate (29.4/1,000) and mortality rate diagnostic test (RDT). There were two types of (19.4/100,000) were reported in 2001. 85 OSIR, September 2019, Volume 12, Issue 3, p.84-92 Figure 1. Trends of malaria morbidity rate (per 1,000 population) and mortality rate (per 100,000 population) in Eastern Shan State, Myanmar, 2000-2016. Note: RDT: rapid diagnostic test. Proportion of Malaria among All Hospital Cases and lowest morbidity rate (12.4/1,000). In 2016, there was Deaths, 2000-2016 a 78% reduction in morbidity rate and a 96% reduction in mortality rate in Mong Tong Township In 2000, there were 11,810 reported outpatient (OP) compared to 2000. The lowest morbidity rate in 2016 and 1,801 inpatient (IP) malaria cases. Only 83 among all townships was in Mong Lar (0.1/1,000). malaria deaths were reported. The highest peak of OP and IP cases occurred in 2003 (16,102 and 2,144 Coverage of Case Detection and Annual Blood cases, respectively). Between 2000 and 2016, there Examination Rate by Township was a 75% reduction in OP malaria cases, a 92% Figure 3 shows the annual blood examination rates reduction in IP cases and a 98% reduction in malaria (ABER) in Eastern Shan State according to township deaths. The proportion of malaria cases among total in 2000, 2005, 2010 and 2016. In 2000, all the patients decreased among both OP and IP cases. In townships reported an ABER of less than 5.0% except 2000, there were 80,567 out-patients, of whom 11,801 for Mong Hsat Township which had an ABER of (14.6%) were malaria cases while of the 253,443 out- 10.6%. Case detection rates increased over the years patients in 2016, only 2,917 (1.2%) were malaria from 2000 to 2016. In 2016, all townships reported an cases. A decrease in the proportion of IP malaria ABER of more than 5.0% and Mong Yang township cases was similarly observed. In 2000, there were 330 had the highest rate of 29.4%. deaths from all causes in hospitals of which 83 (25.2%) were from malaria. In 2016, of 126 deaths in hospitals, Distribution of Malaria Cases by Month only 2 (1.6%) were malaria-related.